UPDATE (9th February 16:22 BST): This article has been updated with new information regarding BTCC’s bitcoin and litecoin withdrawal policy.

Yuan recharge, withdrawals and other services will not be affected, the exchanges said.

In public posts that showcase the increasingly coordinated nature of exchange policy in the region, both OKCoin and Huobi said today that the move was a bid to bolster their anti-money laundering (AML) capabilities and prevent "illegal transactions". In the case of OKCoin, only it's OKCoin.cn portal is affected.

Both OKCoin and Huobi indicated that their platforms would now go through an “upgrade” to combat “money laundering, exchange, pyramid schemes and other illegal activities”, though no further details were provided.

Following the publication of this article, BTCC announced that it would also upgrade its internal systems. In the meantime, the exchange said, bitcoin and litecoin withdrawals will take 72 hours to process.

All told, the move comes amid a rocky period for local exchanges that began with the wider scrutiny of major bitcoin exchanges by the People's Bank of China (PBOC), the country's central bank.

Earlier today, China's central bank issued a warning to domestic exchanges, going so far as to state it would move to shutter startups that violated its guidance through the necessary government channels.

In statements provided to CoinDesk, Huobi indicated that the move was a proactive one that found the two exchanges seeking to "promote bitcoin industry self-discipline".

Update: This article has been updated to clarify that only OKCoin's OKCoin.cn platform is affected by the withdrawal freeze. 

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